package com.zc.dem.common.synmessage;

import javax.xml.bind.*;
import javax.xml.bind.annotation.XmlAnyElement;
import javax.xml.namespace.QName;

import org.apache.commons.lang3.StringUtils;


import java.io.File;
import java.io.InputStream;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Collection;

/**
 * 使用Jaxb2.0实现XML<->Java Object的Binder.
 * 特别支持Root对象是List的情形.
 */
public class JaxbBinder
{
    //多线程安全的Context.
    private JAXBContext jaxbContext;
    
    /**
     * @param types 所有需要序列化的Root对象的类型.
     */
    public JaxbBinder(Class<?>... types)
    {
        try
        {
            jaxbContext = JAXBContext.newInstance(types);
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Java Object->Xml.
     */
    public String toXml(Object root, String encoding)
    {
        try
        {
            StringWriter writer = new StringWriter();
            createMarshaller(encoding).marshal(root, writer);
            return writer.toString();
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Java Object->Xml, 特别支持对Root Element是Collection的情形.
     */
    @SuppressWarnings("unchecked")
    public String toXml(Collection root, String rootName, String encoding)
    {
        try
        {
            CollectionWrapper wrapper = new CollectionWrapper();
            wrapper.collection = root;
            
            JAXBElement<CollectionWrapper> wrapperElement =
                new JAXBElement<CollectionWrapper>(new QName(rootName), CollectionWrapper.class, wrapper);
            
            StringWriter writer = new StringWriter();
            createMarshaller(encoding).marshal(wrapperElement, writer);
            
            return writer.toString();
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Xml->Java Object.
     */
    @SuppressWarnings("unchecked")
    public <T> T fromXml(String xml)
    {
        try
        {
            StringReader reader = new StringReader(xml);
            return (T)createUnmarshaller().unmarshal(reader);
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * 创建Marshaller, 设定encoding(可为Null).
     */
    public Marshaller createMarshaller(String encoding)
    {
        try
        {
            Marshaller marshaller = jaxbContext.createMarshaller();
            
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            
            if (StringUtils.isNotBlank(encoding))
            {
                marshaller.setProperty(Marshaller.JAXB_ENCODING, encoding);
            }
            return marshaller;
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * 创建UnMarshaller.
     */
    public Unmarshaller createUnmarshaller()
    {
        try
        {
            return jaxbContext.createUnmarshaller();
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * 封装Root Element 是 Collection的情况.
     */
    public static class CollectionWrapper
    {
        @SuppressWarnings("unchecked")
        @XmlAnyElement
        protected Collection collection;
    }
    
    @SuppressWarnings("unchecked")
    public <T> T fromXML(String fileName)
    {
        return (T)fromXML(new File(fileName));
    }
    
    @SuppressWarnings("unchecked")
    public <T> T fromXML(File file)
    {
        try
        {
            Unmarshaller unmarshaller = createUnmarshaller();
            return (T)unmarshaller.unmarshal(file);
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
    
    @SuppressWarnings("unchecked")
    public <T> T fromXML(InputStream stream)
    {
        try
        {
            Unmarshaller unmarshaller = createUnmarshaller();
            return (T)unmarshaller.unmarshal(stream);
        }
        catch (JAXBException e)
        {
            throw new RuntimeException(e);
        }
    }
}
